Tekira Posted December 17, 2003 Share Posted December 17, 2003 I have a 74 260 and i just bought tripple mikunis, msa 3n2 headers and twice pipes. Instead of running the muffler Through the stock location, the back left, I wanted to run it strait out the back. so the muffler will be in the middle of the back like an old ferrari or tr6. The gas tank is right there so i was wanting to know how close i can run the muffler to the tank. Thx, Josh Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted December 17, 2003 Share Posted December 17, 2003 You could always weld a sheetmetal hat over the pipe ( /- , the small dash should be at the top ) to act as a heat shield. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted December 17, 2003 Share Posted December 17, 2003 I've seen exhausts within a quarter inch of the tank before with no apparent problems. As long as no contact is made you're safe, but rubber or bushing mounted exhausts allow a lot of movement, and rubbing is where the trouble starts. Quote Link to comment Share on other sites More sharing options...
Dan Juday Posted December 17, 2003 Share Posted December 17, 2003 It sounds like you want to mount the muffler under the fuel tank. While heat is a ligitimate concern the real problem is space. Mounting the muffler under the tank is not only a challenge on how to hang it but also ground clearance. And it has the potential of looking pretty hokey. I've seen a Z with the muffler in the stock location and then the tailpipe routed the an exit in the middle. In that case the tailpipe was very close to the tank. Then there is always my solution. But that is a little extreme for most people. Quote Link to comment Share on other sites More sharing options...
TomoHawk Posted December 17, 2003 Share Posted December 17, 2003 You could theoretcally run the pipe THROUGH the gas tank if you wanted to. The heat would make the gasoline boil, keeping the temperature down. Then you end up with vaporized gas(not good). Practically, you should probably use some insulation between tank and pipe, so you don't boil the gas any way. Use caution with this one, of course. Quote Link to comment Share on other sites More sharing options...
ZR8ED Posted December 17, 2003 Share Posted December 17, 2003 I suppose it would also depend on which tank is in a 260?.. I'm not sure.. I think it is pretty flat underneath.. I know the 280 style like mine is VERY low, and can easily be seen under the car.. On a 280 it would be very hard...a 240/260 with the flatter tank underneath would have a few more inches of space.. As for a shield, use aluminum.....heck..while your at it...(oh oh did I just say "while your at it") AAAAHHHHH make a nice wide one....like a rear belly pan...yea thats it...a rear belly pan...have the muffler under it... put in some vertical fences on either side of the muffler, and on both edges, and wala.. tres' cool.. i have my muffler in the stock place, but I'm putting in my belly pan under the muffler and fuel tank.....(my 280 tank hangs lower than a stock placed muffler) Quote Link to comment Share on other sites More sharing options...
TomoHawk Posted December 18, 2003 Share Posted December 18, 2003 If you're going to modify things, why not just try a different fuel tank? I mean one that has a tunnel down the middle, or even two tanks grafted together, with the tunnel down the middle. that way you could put the exhaust pipe where you want, as long as you build the fuel tank the right way. Quote Link to comment Share on other sites More sharing options...
Tekira Posted December 18, 2003 Author Share Posted December 18, 2003 Well after thinking and looking at the tank it would look a little "hokey" as Dan so elequently put it. i can make it look good with the tank being there and using a heat shield but i would look great if it wasn't. I am thinking Fuel cell in spare tire compartment. Any one know the prices of fuel cells. If too expensive i can live with a little bit a muffler showing. or maybe i could get a rear valence to "extend" the length to hide the muffler better. I would want it to have the same stock shape just longer, anyone know of one. Thx, Josh Quote Link to comment Share on other sites More sharing options...
alternativez2003 Posted January 7, 2004 Share Posted January 7, 2004 Many exhaust are centered: Mini S, old 2002 BMW's, etc. Just look at how they did it. Check out the early Pete Brock BRE Z racers. Of course the racers had fuel cells, but the exhaust in the center can look cool, and it seems more efficiect in terms of flow. I like that the straight system would be less cluttered than the 240 system's sharp bends to get around the gas tank. I am putting my 85 635 BMW engine et al into my 1970Z and intend to run the exhaust straight out the center just as it does on the 635. I haven't determined the method, but I may cut into my Z tank, or use the 635 tank in some way. I have considered removing the spare tire tub if necessary. I plan to use run-flat tires anyway... A possible problem is fitting enough exhaust components into the shorter length. It just means there is very little tubing between cat, mufflers, and resonators. I intend to keep my Z a little quieter than the 635 is stock. It has a very solid big six rumble which is nice, but can be too much for not-so-affected passengers on longer drives. Just have to turn up the tunes, I guess. Another possible drawback is having the hot tailpipes and exhaust exiting at the center; if you are loading the rear with the engine running, you have the exhaust in your face, or at least at your legs. Consider if that will be a concern for you and anyone else using your car: hot summer day, shut off the car and go stand at the rear to unload the picnic... Also, keep in mind the the turbulence at the rear and the worry of exhaust fumes entering the cabin. On a 327 Z I did many years ago, a body shop friend did a nifty little surround over the top of my exhaust tips which helped the appearance as they exited the rear valance in the stock position. Many cars now do such a design touch, and it really looks nice, and it may help the air flow around the tips to help disperse the fumes. As far as looks, I would again look at how other cars have taken car of the design. Good luck, Jim Quote Link to comment Share on other sites More sharing options...
Tekira Posted January 13, 2004 Author Share Posted January 13, 2004 AAH screw this stupid twice pipes system. I tried for hours to get the dam things on right and they wont even hang in stock locations. The muffler hits the tire. I have had them in my garage for not even a month and they are getting rust deposits allready. Tried to make some custom brackets to hang muffler in the middle like i said, but i just could'nt get it where i wanted it. Damn muffler doesnt want to be on the car i guess. i didnt bend the pipes so i sent it back. I got a better idea thou. Buy some 2.5 inck exhaust tube and run it right out the middle with a 30 degree bend upwards before the tank. Nice and loud. Kinda like the bre car but bent up like old alfa or ferrari. But first i got to put all new fuel lines in. Got some rust under the battery that rusted the fuel lines also. I just got the msa 3n2 headers on right now and umm... its just a little loud. I was thinking black powder coat on the end of the pipes would look good. any way thx fof the help. Thx, Josh Quote Link to comment Share on other sites More sharing options...
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